Robert Downey Jr. learned "what [he] wasn't" as a performer thanks to his brief stint on 'Saturday Night Live'

Speaking on new docuseries 'SNL50: Beyond Saturday Night', he said: "I learned so much in that year about what I wasn't. But there's not a more exciting 90 minutes you could have, whether you are any good or not."

The 'Oppenheimer' star got the job on the sketch show thanks to his good friend Anthony Michael Hall.

He said: "Michael Hall said to me, 'I'm gonna go do 'SNL'. I'm gonna get you an audition and I bet you're gonna get yourself on the show too.' "

Anthony joked he's still waiting for his pal to "repay a favour" as a result.

He quipped: "I'm still waiting for that b****** to repay a favour, 40 years later. Come on Iron Man, you got it in ya."

Anthony himself was the show's youngest ever cast member at just 17 years old and he recalled it being a challenging time.

He said: "When I look back, I have some memories of it being difficult.

"I think - for a lot of the writers to figure out how to write for this kid - I think it was a big challenge."

The two stars appeared on season 11 of 'SNL', which is widely considered to be one of the show's weakest periods and many of the cast - including Joan Cusack and Randy Quaid - were swiftly dropped.

Looking back, showrunner Lorne Michaels acknowledged he had wanted to "clean house" and bring in a new generation of performers for 'Saturday Night Live', but ultimately went for people who were "too young".

He reflected on the docuseries: "I wanted to go younger. I perhaps went too young, but I wanted to go younger. The Baby Boomer generation had dominated the show for 10 years, so I decided to clean house."